Process of preparing dialkylbarbituric acid.



Patented November 22, 1906;.

arieur price.

MAX EN GELMANN OF ELBERFIELD, (lERh TAN \V', ASSIONOR TO FARBEN-FABRIKEN OF ELBERFELI) 00., OF NEW YORK, .N. Y., A CORPORATION OF NEWYORK.

PROCESS OF PREPARlNG SPECIFICATION formingpart of Letters Patent No.775,810, dated November 22, 1904.

Application filed August 4, 1904:-

To all whom it ill/my concern:

Be it known that I, MAX ENG ELMANN, doctor of philosophy, chemist,residing at Elberfeld, Germany, (assignor to the FARBENFABRIKEN orELBERFELD 00., of New York,) have invented a new and useful Improvementin Processes of Preparing Dialkylbarbituric Acids; and I do herebydeclare the following to be an exact and clear description of myinvention.

My invention relates to a new process for the production ofdialkylbarbiturie acids (2-4- 6-trioxy-5dialkylpyrimidins) having thefollowing general formula:

NH--CO l a co c l NH--O (R meaning alkyl radicals) which bodies possessvaluable therapeutic, especially soporific, properties. The process forthe preparation of these compounds consists in first condensingthio-urea (thio-carbamid) with dialkylated malonitrils of the generalformula Re I C I (ON): by means of alkaline condensing agents; seeondly,splitting oil the imino groups and replacing them by oxygen in 4 and 6position from the resulting 2-thio-t-ddiimino-5-dialkylpyrimidins of thegeneral formula NH O N H i R l s:c c

l B NH----O I NH by treatment with saponifying agents, and, iinally,desulfurizing the 2-thio-4-6-dioxy-5-dialkyl-pyril'nidins thus producedby treatment with oxidizing agents, by which operation the sulfur isreplaced by oxygen.

In order to carry out my process practically, I can, for instance,proceed as follows: Seventy-six parts of thio-urea and one hundred andtwenty-two parts of diethylmalonitril are added to a solution offorty-six parts Serial No. 219,506. (No specimens.)

and the resulting mixture is heated for two 5 f of sodium in livehundred parts of alcohol, I

y body is obtained in the shape of yellowish needles melting at 230centigrade. For the saponiiication fifty parts of the2-thio-4-6-diimino-5-diethylpyrimidin thus produced are heated with onehundred parts of a thirty-per tor-bath. After cooling it is filteredoff, and twenty parts of the 2-thio-4t-6-dioxy-5-di ethylpyrimidin thusobtained are introduced into fifty parts of pure concentrated nitricacid.

The excess of nitric acid is then neutralized by the addition of sodiumcarbonate, and the diethylbarbituric acid thus precipitated is purifiedby a recrystallization from water.

ethylate other alkaline condensing agents--- such as solid alkalinealcoholates, sodium amid, or the like can be employed.

The saponilication and the splitting off of ponifying or other oxidizingagents.

The process proceeds in an analogous manner for the production of otherdialkylbarbituric acids.

what manner the same isto be performed, what I claim as new, and desireto secure by Letters Patent, is-

1. The process for the production of dialgeneral formula, which processconsists in first condensing thiourea with dialkylated malonitrils bymeans of alkaline condensing agents, secondly splitting off the iminogroups in t and i-(i-diimino-o-dialkylpyrimidins by treatment withsaponifying agents, and finally desulfurizing the 2 -thio-4-6-dioxy-5dialkylpyrimidins, thus produced, substantially as hereinbcforedescribed.

2. The process for the production of diethylcent. sulfuric acid forthree hours on the w:

The oxidation is completed in a short time. 5

Instead of an alcoholic solution of sodium 7 sulfur can also be carriedout with other sa- Having now described my invention and in 30kylbarbituric acids having the abovegiven 5 (5 position from theresulting 2thio- 9 barbituric acid, which process consists in firstcondensing thio-urea with diethylmalonitril .by means of alkalinecondensing agents, secting ofl' the imino groups in 4 and 6 positionfrom the resulting 2thio-46-diimino-5-Cliethylpyrirnidin by treatmentWith hot sulfuric acid and finally desulfurizing the resulting2-thi0-4-6-dioXy5diethylpyrimidin by treatment with nitric acid,substantially as hereinbefore described.

In testimony whereof I have signed my name in the presence of twosubscribing Witnesses.

MAX ENGELMANN.

\Vitnesses:

OTTO KONIG, J. A. RITTERsHAUs.

